[amsat-bb] Re: old satellites

Chris Hackworth n8phucjh at gmail.com
Tue Mar 17 21:35:58 PDT 2009


Bit of a lurker here, but my day job is at a Satellite Earth station
for SES Americom, a satellite owner/operator.

Normally, when a satellite is about to run out of  fuel, it is sent
into what is called a graveyard orbit, to keep it from drifting and
running into other satellites. It is boosted high above the
geosynchronous belt where it wont run into anything.

A satellite is usually hard wired for the frequencies in use. Up link
in the C band is usually 5.9 to 6.4 Ghz, and there are 24 TWTs, each
tuned to a 40 Mhz hunk of spectrum.So, Transponder 1 is the first 40,
transponder 2 is the second 40, etc....

At Ku band, it runs from 14 GHZ to 14.5 Ghz. sometimes the transponder
width is 40mhz, sometimes it is 54Mhz. again, the individual TWT is
tuned for its little slice.

All of this filtering is done pre and post amp by hard filters that
can not be changed from the ground.

Without command and control of the satellite, it is for all practical
purposes useless.

Chris Hackworth

On Thu, Mar 12, 2009 at 12:24 AM,  <w7lrd at comcast.net> wrote:
> Hello
> I believe this subject has been kicked around on this BB before.  It did generate some creative thinking.  Given  all the satellites up there and all the varied uses of them, eventually some of them get compromised for whatever reason.  Is there any way any of these old relics can be reprogramed, used or otherwise "adjusted" to suit us?  We don't need a real good S/N  ratio to make us happy, and we are pretty good at cobbling together whatever we want.  We have some very informed and smart people on this BB who know.
> 73 Bob W7LRD
> Seattle
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Chris N8PHU
ET1(SW) USN (Ret)
Chief transmitter Heavy  SES-Americom

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